Final answer:
A fraction of ice is submerged when it floats in water, the water level when the ice melts is c) The water level decreases.
Step-by-step explanation:
Ice is less dense than liquid water and floats, due to its unique structure dictated by its shape, polarity, and hydrogen bonding. When ice melts, it remains at the same volume, but its density increases as it changes from a solid to a liquid. Since the density of liquid water is higher than that of ice, the water level will decrease when the ice melts.
To understand why the water level decreases, consider the Archimedes' principle. According to this principle, when an object is submerged in a fluid, it experiences an upward buoyant force equal to the weight of the fluid it displaces. When ice floats in water, it displaces a volume of water equal to its own volume. When the ice melts, its mass remains the same, but its volume decreases as it changes into a liquid state. As a result, the volume of water it displaces decreases, leading to a decrease in the water level.
For example, if you have a cup of water filled to the brim and you place an ice cube in it, the level of water will rise slightly as the ice cube displaces an equal volume of water. However, when the ice cube melts, the water level will decrease as the melted ice occupies less volume than the ice cube previously did. Therefore the correct answer is c) The water level decreases.